Sometimes thing are just comped complex. I know we want to see epicycles and simplify and be able to reduce the system, and sometimes that's even possible. (Don't get me started on being all in on all of AWS.) But sometimes it isn't and, well, that's where we are as an industry.

I haven't worked at many places like this, but the last time I did they had services that managed and operated on petabytes worth of data. The full suite of front end applications, rest services, ingestion services, maintenance, queues, billing, communication, scheduling and other systems is large enough that I probably only saw the source code for maybe 1/3 at most, let alone modified.

I do like local development better, every time it is feasible, but there's not much point in doing so if it can't reasonably reproduce a production system.